Added scanning barcodes with a camera

quagga2/quagga2-1.12.1/test/integration/reader-order.spec.ts

@@ -0,0 +1,90 @@
+/**
+ * Tests to verify that barcode readers are processed in the order specified
+ * in the configuration. This is important for predictable decoding behavior.
+ * 
+ * Key findings about reader order:
+ * 1. Internal readers (code_128_reader, ean_reader, etc.) are processed in the 
+ *    order they appear in the `readers` config array
+ * 2. External readers must be registered via `Quagga.registerReader()` BEFORE 
+ *    they can be used in the `readers` array
+ * 3. The position of a reader in the `readers` array determines when it attempts
+ *    to decode (earlier = higher priority)
+ * 4. The first reader to successfully decode the barcode wins
+ */
+
+import Quagga from '../../src/quagga';
+import { expect } from 'chai';
+
+/**
+ * Helper function to construct fixture paths consistently across browser and Node environments
+ */
+function getFixturePath(folder: string, filename: string): string {
+    const prefix = typeof window !== 'undefined' ? '/' : '';
+    return `${prefix}test/fixtures/${folder}/${filename}`;
+}
+
+describe('Priority Behavior with Multiple Readers', () => {
+    it('should decode EAN-8 as ean_8 when ean_8_reader is prioritized over ean_reader', async function() {
+        this.timeout(20000);
+        
+        // This test uses an EAN-8 barcode image (8 digits)
+        // When ean_8_reader is listed first, it should decode as ean_8
+        const config = {
+            inputStream: {
+                size: 640,
+            },
+            locator: {
+                patchSize: 'large',
+                halfSample: true,
+            },
+            numOfWorkers: 0,
+            decoder: {
+                // EAN-8 reader first - should decode EAN-8 barcodes as ean_8
+                readers: ['ean_8_reader', 'ean_reader'],
+            },
+            locate: true,
+            src: getFixturePath('ean_8', 'image-001.jpg'),
+        };
+        
+        const result = await Quagga.decodeSingle(config);
+        
+        expect(result).to.be.an('object');
+        expect(result.codeResult).to.be.an('object');
+        expect(result.codeResult.code).to.equal('42191605');
+        expect(result.codeResult.format).to.equal('ean_8');
+    });
+    
+    it('should fallback to ean_8_reader when ean_reader cannot decode EAN-8 barcode', async function() {
+        this.timeout(20000);
+        
+        // EAN-8 and EAN-13 are different barcode formats with different structures.
+        // The EAN-13 reader will not successfully decode an EAN-8 barcode,
+        // so it will return null and the decoder will try the next reader.
+        // This test demonstrates that reader order affects fallback behavior.
+        const config = {
+            inputStream: {
+                size: 640,
+            },
+            locator: {
+                patchSize: 'large',
+                halfSample: true,
+            },
+            numOfWorkers: 0,
+            decoder: {
+                // EAN-13 reader first, EAN-8 as fallback
+                readers: ['ean_reader', 'ean_8_reader'],
+            },
+            locate: true,
+            src: getFixturePath('ean_8', 'image-001.jpg'),
+        };
+        
+        const result = await Quagga.decodeSingle(config);
+        
+        // EAN-13 reader cannot decode EAN-8, so EAN-8 reader succeeds as fallback
+        expect(result).to.be.an('object');
+        expect(result.codeResult).to.be.an('object');
+        expect(result.codeResult.code).to.equal('42191605');
+        // Since EAN-13 reader fails, the EAN-8 reader handles it
+        expect(result.codeResult.format).to.equal('ean_8');
+    });
+});